content: /*
   * Copyright 2016-present David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.basetypes;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.internal.subscriptions.SubscriptionHelper;
  
  /**
   * Basic subscriber that supports queue fusion and defaults onSubscribe, onNext and cancel.
   */
  abstract class BasicNonoSubscriber extends BasicEmptyQueueSubscription implements Subscriber<Object> {
  
      protected final Subscriber<? super Void> downstream;
  
      protected Subscription upstream;
  
      BasicNonoSubscriber(Subscriber<? super Void> downstream) {
          this.downstream = downstream;
      }
  
      @Override
      public void onSubscribe(Subscription s) {
          if (SubscriptionHelper.validate(this.upstream, s)) {
              this.upstream = s;
  
              downstream.onSubscribe(this);
          }
      }
  
      @Override
      public final void onNext(Object t) {
          // never called
      }
  
      @Override
      public void cancel() {
          upstream.cancel();
      }
  
  }
  